Give some uses of LED. How should LED be connected?

Give some uses of LED. How should LED be connected ?
A. (a) as indicators in electrical appliances.
(b) as a point source of light in laser beam torches.
© LEDs emitting white light can be used instead of bulbs.
The longer lead (leg) from the LED should be connected to the positive terminal of the battery and the shorter lead to the negative terminal of the battery.